Fluid operated tool



Aug. 8, 1933. R, HOFFMAN FLUID OPERATED TOOL Filed April 29, 1951 2 Sheets-Shee t 1 ZSmaentor H 1 .m m kJw Mm. m z i a w (Ittornega.

Aug. 8, 1933.

J. R'. HOFFMAN FLUID OPERATED TOOL Filed April 29, 1931 2 Sheets-Sheet 2 Patented Aug. 8, 1933 PATENT OFFICE FLUID OPERATED r001. 1

, John R. Hoffman, Madisonpwis assignor to Madison-Kipp Corporation, Madison, Wis., a

Corporation of Wisconsin it I Application April 29, 1931. Serial No. 533,809

3 Claims.

This invention relates to fluid-operated tools, and especially to those of the reciprocatory type, such as files, saws and the like. a y I The primary purpose of the invention is tofurnish a small, practical tool of the character m'en-- f tioned adapted for shop or general use. The body of the tool is designed to permit thetool'to be held in anatural position inthe hand, thereby facilitating operation of the tool in any position and adapting it for easy access to all types of work. Manufacture of the parts of the lightest metal possible consistent with eiiiciency, also aids materially in the facility with which the tool may be operated. Further provision is made for enabling the toolelement to be guided readily over irregular surfaces. A particularly important feature ofthe' device consists of the improved means for controlling distribution of the motive fluid which actuates the piston connected to the reciprocating tool body;

By thesemeans, direct and complete control of.

the fluid is maintained: during. its passage through the tool. In'additiomthe fluid-distributing means are designed to cause a special retarding effect on the movements of the piston which .ishighly desirable in certain tools of this type.

Particular provision is made for the elimination of all vibration in the operation of the tool,

thereby effecting smooth cutting strokes of the tool element. 7

A further feature is the efficient utilization of the exhaustfluid tooperate the means for distrib uting the motive fluid to the power cylinder. Use is also made'of the exhaust fluid to aid in slowing up the reciprocatory movement of the piston.

Other objects will appear hereinafter.

Referenceis had to the accompanying drawings showing a practicalembodiment of my invention, and in which':-

Fig. 1 is a side elevation of the tool; Fig. 2, a rear elevation thereof, partly broken away'to show the rotor for operating the fluiddistributing valve;

showing the fluid supply valve closed and'the piston in mid-position completely closing the cylin Fig. 3, a section taken on line 3 3: of Fig. 4,

Fig. ,9, a side elevation of the same; a Fig. 10, a section on line 1010 of Fig. 9, showing the segmental fluid-distributing groove for the'motive fluid; Fig. 11, aside elevation of the bushing or bearingfor the distributor valve; i J

Fig. 12, a section taken on line 12--12 of Fig. 1 1; i

Fig. 13,, afragmentary sectionsimilar to. Fig. 3, showing a succeeding position of the parts as thewfluid supplyvalve is opened to .feed motive fluid to the right vend 0f the cylinder and force the piston slightly to theleft; i Fig. 14, a similar view as the piston continues its movement to the left to open the exhaust port, and'the distributing valve'begins to feed fluid to the left end'of the cylinder; i 1 Fig. 15; aslmilar view showing the piston forced to' the right end of the cylinder,]again opening the exhaust port as continued rotation of the valve causes fluidto be fedbnly to thefleft end of the cylinder.

In the drawings, thebody 1 of the tool, which preferably. is .a die-casting of zinc or other suit-j able light metal, is formed with a. handle 2 and a barrel 3. The tool body, as shown most clearly in Fig.1, isgdesigned so 'as to simulate closely a" standard-'typeipistol or revolver. The pistol grip thus provided greatly increases the ease and accuracy-with which the tool may 'beghandled under all conditions. V t

The tool-element actuating piston 4 is located for reciprocation in-a cylinder 5 formedin the upper part of the tool body. A-piston rod 6 extends from piston 4 through the .barrel of the tool and at its forward end is provided with a chuck 7 adapted to receive any desired type tool steel or element, shown in this instance asa An extended bearing for piston rod '6 is atforded by the reduced passage 9 at theinner end of barrel 3. 'A bushing 10 threaded into the end" of the main barrel chamber 11' provides a suitable bearing for the outer end of piston rod 6. Piston rod 6*and bushing 10 are keyed together suitably at12 so asto preventrotationof the piston rod without-interfering with thereciprocatory movement thereof necessary to operate the file 8.

Screw plugs 13, 14 at the rear end of cylinder '5 provide for ready removal or insertion of piston 4 and piston rod 6 when desired. Detachment of file 8 and collet nut '7 of the chuck from the forward end of pistonirod 6 isnecessary, of'

tributing valve or shaft 31, theleft endof which course, before the piston rod and piston 4 can be removed.

The means for controlling supply of motive fluid to the tool and distributing it in order to effect the desired reciprocation of piston 4, piston rod 6 and the attached file as a unit willbe described now.

Piston cylinder 5 is provided with forward and rear fluid inlet 'ports 15, 16, respectively, and a single exhaust port 1? controlled by piston 4. Motive fluid, preferably compressed air, is supplied to the lower end of a passage 18 in the handle of the tool by a flexible tube 19 leading from a suitable source of supply. From passage 18 the motive fluid is adapted to be conducted alternate- I ly to opposite sides of piston 4 through inlet ports 15, 16, as described below.

Supply passage 18 opens at its upper end into a valve chamber 20. The rear end of chamber 20 is closed by a screw plug 21, while the forward end of thevalve' chamber opens into a smaller chamber 22.. A throttle valve 23 controls communication between chambers '20 and 22, a spring 24 serving normally to hold valve 23 closed and thereby prevent passageof motive fluid beyond this point. Stem 25 of valve 23 projects forwardly through an opening-in the tool handle for engagement by a valve actuating trigger 26 pivoted on a pin 27 carried by the barrel of the tool. a

When control valve 23 is operated by trigger. 26,

as shown in Fig. 13, compressed 'air enterspasa sage 22, and thence flows into'an inclined'passage' 28 (Fig. 4). The upper end of passage 28.1eads to anopening 29 in a bushing or bearing mem-.

ber 30 fixedly located in a suitable transverse opening provided in the. body of thetool. This bushing30 is shown in detail in Figs. 11 and 12.

Mounted for rotation in bushing 30 'is a disbecoming detached or loosej Towards its right end, valve shaft 31, as show in Fig. 4, is formed with an annularsgroove 33 into which the. motive fluid enters from opening .29 in bushing 30. Fromannularigroove 33 the motive fluid is conducted through a longitudinal grove 34, and thence into a transverse segmental groove 35', all of these grooves being formed in the body of the distributor valve.

Segmental groove 35 is located in alinement with two openings 36, 37 provided in bushing 30.

' These openings connect with a pair of passages seen that motive fluid entering segmental groove 15, 16 of piston cylinder 5.

35 will be distributed thereby alternately to inlet ports 15, 16, effecting the desired reciprocation,

of piston 4, when properly assisted by the fluid r exhausting mechanism described shortly.

' It will be noted that the angular extent of segmental groove 35 is such that, as shown most clearly in Fig. 14, the groove serves to start feeding motive fluid to one of the cylinder inlet ports P15, 16 just as it begins to discontinue the feed bushing 30.

of motive fluid to the other inlet port. The purpose of this will appear hereinafter.

Piston cylinder 5 is provided with a single centrallylocated exhaust port 17 (see Fig. 3), which is adapted to be entirely closed by piston 4 when the latter is in its mid-position. How ever, when piston 4 is moved toward either end of its cylinder, the motive fluid which has effected this movement of the piston escapes from exhaust port 17 and enters a segmental groove 41 formed on the outside of the distributor valve The angular extent of groove 41 is such that at its lower ends, as shown in Fig. 3, it communicates with horizontal passages 42, 43 formed in the body of the tool.

Extending from the ends of these passages 42, 43 are angularly disposed reduced passages 44, 45 opening into the rotor chamber 46 for the purpose of ejectingthe exhaust motive fluid against the buckets 47 of the rotor 32 to operate the latter. This, as stated hereinbefore, serves to impart thenecessary rotary movement to the distributor valve 31 in order to feed the motive fluid to the piston cylinder. For sake of clearness, the course which the exhaust fluid takes is indicated by arrows in Fig. 1, although in this figure piston 4, is not, in fact, in fluid-exhaust-- the actuating means for the motive fluid distributing valve.

. The outer side of rotor chamber 46 is closed by a cap 49 threaded in place, and provided on its inner face with a central depression containing a single ball bearing 50. When cap 49 is screwed into. place, ball 50 forms an effective thrust bearing for rotor 32 and its fluid-distrib uting shaft 31. The exhaust motive fluid escaping from the periphery of rotor 32 passes out of rotor chamber 46 through an outlet opening 51 (see Fig. 1). Spanner wrench sockets 52, 53 in the outer face of the rotor chamber covering 49 provided for ready removal and replacement of this member.

The purpose of arranging segmental groove 35 in distributor valve 31 so that communication between it and one of the inlet ports 15, 16 is not cut off before communication with the other port is opened, is to slow down the reciprocatory movement of piston 4 and the attached tool part. This is highly desirable in certaintools, particularly those of the file type. This arrangement of the distributing means also prevents excessive hammering of the piston and reduces vibration in the tool. Also, since segmental groove 35, duev to its angular extent, is always in communication with either inlet 15 or 16, no matter what the position in which distributor valve stops, starting of the tool is assured when the throttle valve 23 is opened.

Reference is now had to Figs. 13, 14' and 15 which disclose the various positions of thetool parts in operation. In Fig. 13, the motive fluid is shown as entering the cylinder inlet port 16, being fed thereto by the segmental groove 35 in distributor valve 31. Itwill be noted that at this time groove 35 is only in communication with inlet port 16,- thereby forcing piston 4 to the left. At this time, exhaust valve 17 is about toopen and permit the motive fluid at the right of piston 4 to -escape.' i

As rotation of distributor valve31-c0ntinues; this-movement being-in a counterclockwise direction, piston 4 moves further to the left, but just before it-r'eaches its extreme position, segmental groove 35, as shown in Fig. 14, communicates partially with the opposite inlet port 15. It will be noted that this occurs before communication between segmental groove and inlet port 16 has been cut off. As a consequence, a small quantity of motive fluid is fed into the space between piston 4 and the end of its cylinder before the piston has reached the end of its movement. This provides an effective cushioning of the piston movement, and not only cuts down excessive hammering, but provides for the very desirable slowing down of the movement of the piston.

When the parts have reached this position, exhaust port 17 is in full open condition, permitting the exhaust fluid to escape and pass to rotor chamber 46 to operate the rotor and the attached distributing valve, as described hereinbefore.

Leaving the parts as shown in Fig. 14, distributor valve 31 continues its rotary movement, thereby cutting off communication with inlet port 16 and moving into full communicationwith inlet port 15. This forces piston 4 back to the right,

'but prior to the piston reaching its right hand .31. From this point, the movements of the parts are continued as described above, the piston 4 and the attached tool part being moved steadily back and forth as a result of the automatic functioning of the fluid distributing means.

In order to aid further in slowing down the "reciprocatory movements of piston 4, provision is made for by-passing a portion of the exhaust motive fluid, so that it does not function to operate the distributor valve. In some cases, it is found that utilization of all of the exhaust fluid 'for this purpose causes the distributor valve to operate too fast, thereby effecting excessively rapid reciprocation of the file 8. As shown in the present embodiment of the invention, a by-pass .or port 54 (see Figs. 1 and 4) is provided in piston cylinder 5 in transverse alinement with exhaust port 17. With this arrangement, both the exhaust port and by-pass 54 are adapted to be controlled by piston 4 in its movements back and forth in the cylinder. By-pass 54 opens into rotor chamber 46 (see Fig. 4) and such of the exhaust fluid as escapes therefrom, when the port is uncovered by piston 4, escapes with the rest of the exhaust fluid through outlet 51 in the rotor chamber.

. .manner, the exhaust fluid escaping from port 54 serves to imparta drag or braking effect on the In this movement'of the rotor. This reduces thespeecl of rotation of distributor valve 31 andslows down the movements of piston4, as will be understood readily. 1

Suitablelubricating means are provided in the handle of the tool. These means are intended to supply lubricant to'the motive fluid so that when the fluid passes through the tool, the va= rious parts will be properly lubricated. For this purpose, there is located in fluid supply passage 18 a spool 55, provided with outwardly flaring flanges at its opposite ends to frictionally support the spool in place. Surrounding the body of spool 55 is a layer of absorbent material 56 which may be saturated with lubricant supplied thereto by removing screw plug 5'7 (Fig. 4) located in the handle of the tool. Openings 58, 59 at op-.

ply control valve, since these features form part of the subject matter and are claimed in my prior applications, Serial No. 512,446, filed January 30, 1931, and Serial No. 512,700, filed January 31, 1931 (Patent No. 1,899,150). Also certain features of the fluid-distributing means. and

the lubricating meansdescribed herein are covered by said earlier applications.

The provision of bushing 10 at the outer end of barrel 3 affords means for readily guiding the tool over uneven surfaces, when a file element or the like is being used. In this case, the operator grips the outer end of bushing '10, which is faceted for this purpose, as shown at 10 in Fig. 1, between the thumb and index finger of one hand and grasps the handle 2 with his other hand. The threaded connection between the bushing and the barrel of the tool permits the operator to rotate the bushing while the tool proper is held steady. In this manner, the file element 8 may be twisted and turned by means of bushing 10, because of the keyed connectionlZ between these parts. Ordinarily, however, bushing 10 is screwed tightly in place and the file 8 is guided mainly by the hand in which the tool handle is grasped.

While a practical tool has been illustrated and described herein, it is obvious to those skilled in the art that various changes in the construction may be made Within the scope of the invention, except as the same may be limited by the appended claims.

What is claimed is:-

1. In a fluid-operated tool, the combination of a tool body having a chamber provided with inlet ports; valve means for feeding motive fluid to said inlet ports; means for operating thevalve means by the exhaust fluid from'said chamber; and a piston in the chamber controlling a pair of different-sized, transversely alined exhaust ports, the larger of which supplies actuating fluid to the valve operating means, while the other directs a jet of fluid against the valve operating means so as to retard movement thereof.

2. The combination in a fluid-actuated tool of a body having a piston chamber with inlet ports opening therein; a piston located in said chamber and adapted to control an exhaust port and a relief port; a rotary valve for distributing moa rotary valve controlling distribution of motive fluid to the inlet ports; a rotor for operating the valve; a bushing in which said valve rotates, the exterior of the bushing being formed with a segmental groove connecting said exhaust port with passages leading to the rotor for actuation thereof by the exhaust fluid; and valve means for, controlling supply of motive fluid to the distributing valve.

- JOHN R. HOFFMAN. 

